The present invention relates to an optoelectronic apparatus for the dimension and/or shape checking of pieces including a plurality of substantially planar and mutually parallel surfaces, comprising a base, a locking and referring system for a piece to be checked, detecting means with an optoelectronic system for providing signals indicative of the dimensions of the piece to be checked, a rotary structure, one of said locking and referring system and optoelectronic system being coupled to the rotary structure, and a system for the longitudinal displacement that is coupled to the base and defines a longitudinal axis, the rotary structure being fixed to the base or to the longitudinal displacement system for allowing longitudinal translation and reciprocal rotational displacements about the longitudinal axis between said piece and said optoelectronic system, the optoelectronic system providing said signals in the course of said reciprocal rotational displacements.
The invention also relates to an optoelectronic apparatus for the dimension and/or shape checking of pieces with abutment surfaces and a plurality of substantially plane and reciprocally parallel elements, comprising a base, a displacement system coupled to base that defines a longitudinal axis and comprises a slide for performing translation displacements in a direction parallel to said longitudinal axis, a rotary structure for performing rotational displacements about said longitudinal axis, a first driving system, coupled to the rotary structure f or controlling said rotational displacements , a first transducer for providing signals depending on the angular position of the rotary structure, a second driving system, coupled to the displacement system for controlling said translation displacements, a second transducer for providing signals depending on the position of slide with respect to base, an optoelectronic detecting system comprising a support with a substantially C shape, with two free ends and a central portion, and at least an emitter device and at least a receiver device coupled to the free ends of said support for emitting and receiving, respectively, a beam of light arranged in a plane substantially perpendicular to said longitudinal axis, and a locking and referring system for the piece to be checked with reference surfaces for cooperating with said abutment surfaces of the piece to be checked for defining the position of the piece.
Pieces with a complex shape are present, for example, in a hard disk storage unit of electronic processors. A similar storage unit comprises a xe2x80x9chard diskxe2x80x9d, that consists of a plurality of magnetic disks in which data are stored in sectors arranged in concentric tracks. The magnetic disks are mounted on a rotating spindle in such a way so as to be substantially parallel and generally equally spaced out with respect to each other.
A read/write unit for xe2x80x9chard diskxe2x80x9d includes a support for magnetic read/write heads that comprises a certain number of thin plates or wings substantially arranged on parallel planes, each carrying at least a magnetic head, for example a Hall effect probe head, for reading/writing on one of the disks.
In order to enable the magnetic heads to read/write on all the sectors of the disk, the device for supporting the magnetic read/write heads is coupled with a motorxe2x80x94by means of a bearingxe2x80x94that provides its rotation about an axis perpendicular to the planes defined by the wings.
In order to ensure the proper operation of the read/write unit, the wings of the support for the magnetic read/write heads must be plane, parallel and arranged at prefixed distances from each other, and comply with very tight tolerance limits.
Optoelectronic apparatuses are utilized for the dimension and/or shape checkings of mechanical pieces. These apparatuses comprise, for example, an optoelectronic systemxe2x80x94with a light emitter and an associated receiver for generating and receiving a beam of lightxe2x80x94that rests on a base on which there also rests a support for the piece to be checked arranged in such a way so that the beam of light impinges upon the piece.
International patent application published under n. W087/07007, for example, discloses an apparatus according to the preambles of claims 1 and 15, for contactlessly gauging mechanical pieces with rotational symmetry surfaces, for example crankshafts or camshafts. Such apparatus comprises a frame, two tailstocks, coupled to the frame, for referring and rotating the workpiece, a first optical measuring device, for dinamically checking diametral dimensions, and a second optical mesuring device for checking shoulders of the workpiece, i.e. surfaces that lie perpendicular to the axis of the workpiece.
European Patent Application n. EP-A-0686829 discloses an apparatus for checking crankshafts. The apparatus comprises a base, a headstock and a tailstock, coupled to the base, for referring and rotating the workpiece, and two groups of measuring heads with feelers for entering into contact with cylindrical surfaces of the workpiece and dinamically checking diametral dimensions while the crankshaft rotates about its longitudinal axis.
Even though these apparatuses are generally reliable, they do not guarantee the accuracy required for the checking of pieces with a complex shape, like the supports for the magnetic heads previously referred to, that is a checking becoming even more critical in consideration of the increasing requirement to miniaturize similar pieces.
Object of the present invention is to provide an apparatus for the dimension and/or shape checking of pieces with a complex tridimensional shape that is reliable, precise and particularly accurate, that does not cause piece deformations, in the course of the checking, and is flexible in use.
This and other objects are achieved by an apparatus wherein the locking and referring system is adapted for defining the arrangement of the piece, the latter having a complex tridimensional shape with wings defining the planar surfaces, in such a way so that the plurality of planar surfaces substantially lie on planes parallel to the longitudinal axis, the optoelectronic system being adapted to provide, in the course of the reciprocal rotational displacements, signals indicative of the position of the wings.
This and other objects are achieved by an optoelectronic apparatus wherein the rotary structure is coupled to the slide, the C-shaped support being fixed at its central portion to the rotary structure in such a way that its free ends can perform limited rotational displacements about the longitudinal axis in a plane substantially perpendicular to the longitudinal axis, and the locking and referring system includes an element with a surface that defines a reference plane for the optoelectronic detecting system, and a rapid locking device for cooperating with surfaces of the piece to be checked for defining and locking a position of the piece in such a way so that the substantially plane elements be substantially parallel to the reference plane, the apparatus further including a processing and control unit coupled to the optoelectronic system, to the first and second driving systems and to the first and second transducers for processing the signals sent by the optoelectronic system and by the transducers, and controlling the driving systems.